Negative plate for storage batteries and process for the manufacture thereof.



P. G. SALOM.

NEGATIVE PLATE FOR STORAGE BATTERIES AND PROCESS FOR THE MANUFACTURE THEREOF. APPLIOA' IJIDN FILED JULY 27, 1909.

960,115, u 4 Patented May 31,1910.

I J 'IGZ 1 I I g v I a 4 IIYEVHENETOHR:

P64812901" Jalom,

PATENT OFFICE.

UNITED STATES PEDRO G. SALOM, OF PHILADELPHIA, PENNSYLVANIA.

NEGATIVE PLATE FOR STORAGE BATTERIES AND PROCESS FOR THE MANUFACTURE THEREOF.

To all whom it may concern:

Be it known that l, PEDRO G. Eaton. ct

Phihulclphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful lll'lPlOYGlDQlltS tll Yogatne Plates for Storage Batteries {Hill in Processes for the ltlauui'acture Thereof, i

whereof the following is a specification, reference being had to the accompanying drawings.

In said drawings, 1 have shown a preferred form of conducting support adapted for use in connection with my invention, Which support constitutes the subject of an application filed contcmporaneously herewith, being Serial Number 509,857, but it will of course be understood that my inven-. i

tion is not in any Way limited to the use thereof.

As at present commercially conducted, and apart from theoretical or practically abandoned methods, the manufacture of the negativeplates of lead storage batteries is essentially characterized by the fact that the spongy lead, which constitutes the true active material, is produced in site. That is to say, although. the initial i'nateria'l from which the spongy lead is ultimately to be made, is applied mechanically to the conducting support, the actual conversion hr, as it is technically termed the forming of said material into sponge is eiiected after the application. 1

The object of the present invention is to permit the production of the ultimate active material in bulk, and its application to the support in What may be properly termed its final condition. fected wholly mechanically, and Without any intervention of electrolytic action at that stage of the process.

Referring to the drawings, I will now describe the conducting support, or grid which I find peculiarly Well adapted to use in connection with my improved process.

In said drawings, Figure 1, represents a side elevation of the grid; Fig. H, is a broken vertical section thereof on an enlarged scale, taken on the line ll, II, in Fig. I. Fig. III, is a-broken horizontal section also on an enlarged scale, on the line III, III, in Fig. I.

Said grid consists of an open rectangular frame 1, provided with main bars 2, extending at intervals from top to bottom,

Specification of Letters Patent.

Application filed July 2.7, 1969.

Such application is ef-' Patented May 31, 1910.

- Serial No. 509,855. r i

l and similar main bars 3, extending at intervals horizontally from side to side, with intermediate secondary bars 4, sub-dividing horizontally the rectangular compartments formed by the main bars. The Whole structure is preferably cast integrally from antiinonial lead. I have found that a grid of this form is peculiarly adapted for the application of the active material by hydraulic pressure, which is ellected at one stage of my process.

In the practice of my present invention, I proceed as follows v e l first obtain amass of spongy lead, preferubly by electrolytic deposition or electrolytic reduction, said mass being sufiicient in quantity for the number of plates to be made. After removal from the electrolyte, the spongy lead is thoroughly washed with cold water, and as a result of this treatment, holds a substantial quantity of Water. V hen the spongyv load has been obtained by electrolytic deposition, the particles are usually too large to lend themselves with advantage to the further steps of the process, and I therefore, ureter to pass them through a a L i l v more of about :torty mesh, stirring or rubto properly comminute the crystals. It is then exposed to the atmosphere, so as to permit evaporation of the Water, and, if the mass is large, it may be stirred with advantage to increase the uniformity of this action. As the evaporation proceeds, the temperature of the mass rises somewhat, owing to the fact that lOW oxidation commences, and the primary result is that a thin superficial coating of sub-oxid of lead is formed throughout the interstices of the spongy mass. If this action were allowed to pro ceed indefinitely, as for instance until. the mass became entirely dry through slow evaporation, the conversion into sub-oxid might become so extensive as to substantially change the character of the mass as a Whole. Hence the evaporation, by means of Which I'prefer to effect the limited superficialoxidation, must be arrested at theproper stage. As a practical Working rule, the attaining of this stage may be noted by the feel of the damp mass, W ien squeezed between the fingers. I have found that a condition which corresponds substantially with the temper ot molding sand, is the proper one for arresting the oxidation, and for apbing it in the course of this treatment so as I Q r, 960,115

plying the subsequent process, and" this condition I believe" to correspond Wl'tlllllfi retention of an amount of moisture corresponding to about five per, cent. in bulk of the total mass. In this state, the superficially suboxidized spongy lead is applied to the grid and compressed Within the compartments by the application of heavy pressure.

With a grid Whose actual dimensions were those shown in Fig. I, of the drawings, I

. relation to the electrical desiderata.

If the spongy lead be taken in a thou.

oughly wet condition, and the superficial low oxidation above described has not occurred, the attempt to form it into a battery plate by heavy pressure is liable to rupture or distort the grid, since the mass, withits contained Wtt81,-l3.(3l$ proper compressibility. Even ii themass be actually compressed,-the result will be a coalescence of the leads onge, so that it will assume a practically so id form, either throughout the whole mass, or in localized portions. To'the extent that this condition exists, the plate is impaired for storage battery purposes, since the coalescence of the lead destroys the sponginess, which is oil the essence olf utility. 0nthe other hand, if. the oxida tion be permitted to proceed too far, so as to form a relatively large percentage of lead sub-oxid, the mass 'Will not properly cohere under pressure,and moreover will not be in the desired metallic condition for electrical efficiency. It will therefore be seen that the critical point ofili the process is the controlled oxidation of the; spongy lead to substantially the right point; for lending itself to heavy. compression, v iile still substantially pro-- serv 1g the in e grity of the spongy lead, as such throughopt the great body of the mass.

I have described the above as employed with a lead spdngeproduced by electrolysis, since I consideil this a very desirable adjunct in the preparat ilnfof the material. It s .to be understood however, that I do not limit my claims to this or any other mode of forming the wastage; have described; Itlye pbntrolled'oxidation as being preferably lacnomplished by moistening the mass WlllhllW;},,t,lil and permitting partial evaporation thereof, I do not limit my broad, pr

Il urthcrmorc, while I I ocess yo specific method,

the essential feature being that the oxidatior'i shall be arrested when the mass has, as a whole, the proper consistency for cohesion without substantial coalescence under heavy pressure, and yet substantially maintains the integrity of its metallic condition.

I have found that not only are the plates mogeneous in physical condition and with relation to efficiency for electrochemical reactions, but that they carry a relatively greater quantity of spongy load than can be applied to a given support by the processes now in actual use. Thus, comparing my plate With one made by applying a paste and thcn converting the latter into active material, in site, by the use of an electric current, the relatively greater proportion of lead characteristic of my plate is due to the fact that when spongy lead is 9 formed, from litharge, or other compound of lead,

previously applied to the grid, there is driven ofi in. the act of'conversion, a relatively large percentage of oxygen and reels ture, amounting in somecases to as much as thirty-three per cent'of the total paste or cement initially applied to the plate. It,

therefore, the maximum quantity of paste and cement which can be properly held upon the grid,.be applied in the first instance, the resultant finished plate will contain less than the total amount of spongy lead which the grid is capable of holding. When however, my invention is employed, the maximum amount oi spongy lead can be initially afiplied to. and held upon a grid of given di-- niensions, sincethe actual quantity of lead subcxid is negligible with relation to the embodying my invention, remarkably hoi content oi? the mass as a Whole, Furthermore, the process which forms part of my invention possesses valuable .ieatures of economy as compared with the processes now in use, since the cost oi producing the spongy lead electrolytically, in bulk, and applying it to the grid, is less than the cost of an equivalent amount of litharge, which is the material usually employed for the formation bf the active material.

Having described my invention, I desire to point out that the plate thus obtained differs from the negative plates heretofore employed in theart in the particular that the nally to the plate itself, as distinguished from being electrolytically formed, by the oxidation of the support itself, and the subsequent reduction to spongy lead, in site, (as in the original Plant plate}, and asdistinguished from the method 9 reducing a compound of lead mechanically applied'to the grid, and thus forming the spongy lead by electrolytic action, in site, (as in the BruslnFaure types of plates) 1. An initially formed negative plate active material is initially formed exter Correction in- Letters Patent N 960,115

---for a storage 'battery, consisting of a conducting support and spongy lead particles mechanically applied as such thereto, in a co-herent but non-coalescent mass.

tial coalescence of the lead particles, while' still permitting cohesion thereof, under pressure; and compressing the superficially oxi- 15 dized particles into a coherent but non-coa-' les'cent mass upon a conducting support 3. The hereinbefore described process for the manufacture of negative plates for a storage battery which consists 1n preparing 20 spongy lead particles'in a mass, containing of the case in the Patent Office.

[SEAL] 2. The hereinbefore described. process for" the manufacture of negative plates of a I water, said particles'being initially. formed externally to the plate permitting artial evaporation of the water to occupy y exposure to the air, and thereby producm a. superficial; low oxidation of the partio es; arresting said oxidation when it has progrossed sufficiently to prevent substantial coalescence of the. particles, while permitting cohesion thereof, under pressure; and

PEDRO G. SALOM. Witnesses; I

JAMES H. BELL,

Signed and sealed this 21st day of June, A. D., 191.0.

E. L. FULLERTON.

It is hereby certilied that in Letters Patent No. 960,115, granted May 31,1910, upon the application-of Pedro Salem, of Philadelphia, Pcnnsylyania, for an improve- I lllfillll ltli Negative Platest'ojr Storage Batteries and 'ldrocesscs tor the ll/lanufacturc Tl1ereolT,-an error appears in the printed specification requiring correction as follows: Page 3, line the Word occupy i; should read occur, and that the said Letters Patent should be read with thisicorrection therein that the same inay'contorrn to the record r. Al. TENNANl,

Acting' Commissioner of 1 tntmzfs.

compressing the superficially oxidized par- Correction in- Letters Patent N 960,115

---for a storage 'battery, consisting of a conducting support and spongy lead particles mechanically applied as such thereto, in a co-herent but non-coalescent mass.

tial coalescence of the lead particles, while' still permitting cohesion thereof, under pressure; and compressing the superficially oxi- 15 dized particles into a coherent but non-coa-' les'cent mass upon a conducting support 3. The hereinbefore described process for the manufacture of negative plates for a storage battery which consists 1n preparing 20 spongy lead particles'in a mass, containing of the case in the Patent Office.

[SEAL] 2. The hereinbefore described. process for" the manufacture of negative plates of a I water, said particles'being initially. formed externally to the plate permitting artial evaporation of the water to occupy y exposure to the air, and thereby producm a. superficial; low oxidation of the partio es; arresting said oxidation when it has progrossed sufficiently to prevent substantial coalescence of the. particles, while permitting cohesion thereof, under pressure; and

PEDRO G. SALOM. Witnesses; I

JAMES H. BELL,

Signed and sealed this 21st day of June, A. D., 191.0.

E. L. FULLERTON.

It is hereby certilied that in Letters Patent No. 960,115, granted May 31,1910, upon the application-of Pedro Salem, of Philadelphia, Pcnnsylyania, for an improve- I lllfillll ltli Negative Platest'ojr Storage Batteries and 'ldrocesscs tor the ll/lanufacturc Tl1ereolT,-an error appears in the printed specification requiring correction as follows: Page 3, line the Word occupy i; should read occur, and that the said Letters Patent should be read with thisicorrection therein that the same inay'contorrn to the record r. Al. TENNANl,

Acting' Commissioner of 1 tntmzfs.

compressing the superficially oxidized par- It is hereby certiiied thiit in Letters Patent No. 960,115, grnntvd May 3!, Hill], upon the application-pf Ppdro 1|. ssilomgof Philadelphia, lcnnsyi 'nnin, for an improvement in Negative Plates fo r Storage Batteries and Procmsoa' fol the Manufact uru Thereof, an error appears in the printed specification requiring (:(n'l'ucl-iun as follows: Pug-03, line 23, the wor d occupy should read 000m; and that the Silid Luflm-s lntunl;

should he read with this-correction therein that the same may conform to the record of the case in the Patent Office.

Signcd and sealed this 21st day of June A. 1)., 1910.

[SEAL] F. A. 'llCNNAN'l, 

